Gravel Calculator - Tons and Cubic Yards Needed

Yards or tons? Why you need both

You measure gravel by volume, but most landscape yards and quarries sell it by weight. That is the whole reason a gravel calculator exists. Your driveway needs a certain number of cubic yards; the scale at the yard charges you per ton. The bridge between them is density: how many tons one cubic yard of that particular stone weighs.

Dry crushed stone runs about 1.4 tons per cubic yard. Pea gravel and river rock are a little lighter, around 1.35, because rounded stones leave more air between them. Road base and crusher run are heavier, about 1.5, because the fines pack into the gaps. Wet gravel can weigh 1.7 tons per yard. The calculator fills in a typical density for each material, but if your supplier quotes their own number, type it in. It is the most accurate figure you will get.

How to measure

Measure the length and width of the area in feet, or the diameter for a round fire pit or tree ring. Then decide on depth in inches. As a guide: 2 inches for a decorative top layer, 3 inches for a garden path or patio base, 4 inches for a walkway that gets regular traffic, and 4 to 6 inches of compacted base under a gravel driveway, with 2 inches of surface stone on top. New driveways on soft soil often need 8 to 12 inches total in two or three layers.

The formula

Cubic feet = length × width × (depth ÷ 12). Cubic yards = cubic feet ÷ 27. Tons = cubic yards × density. Then add a margin. Crushed stone compacts by 10 to 15% when you run a plate compactor over it, and loose deliveries always lose a little to spillage and uneven ground, so the calculator adds 10% by default.

The Engineering ToolBox lists dry gravel at about 105 lb per cubic foot, which is 2,835 lb or 1.42 short tons per cubic yard. That matches what most quarries quote for 3/4-inch stone, give or take 5%.

Worked example: a garden path and a driveway

A path 20 ft long, 10 ft wide, and 3 inches deep is 20 × 10 × 0.25 = 50 cubic feet. With 10% extra it is 55 cubic feet, or 2.04 cubic yards. In #57 crushed stone at 1.4 tons per yard, that is 2.85 tons. At $45 a ton, the stone costs about $128 before delivery.

Now a 60 × 12 ft driveway base 4 inches deep: 240 cubic feet, or 9.78 cubic yards with the 10% margin. In road base at 1.5 tons per yard, that is 14.7 tons, which is one tandem dump truck load. Order by the load when you can; the delivery fee is usually per trip, so splitting it into two small loads can double that charge.

Bags vs bulk

Big-box stores sell gravel in 0.5 cubic foot bags that weigh about 50 lb. That is 54 bags per cubic yard, or roughly 1.35 tons of lifting. For a small fire-pit ring or a few pavers, bags are convenient. Past about a ton, bulk from a landscape yard is almost always cheaper, even with a delivery fee, and it saves your back.

Common mistakes

Forgetting to convert depth. 3 inches is 0.25 ft, not 3. Multiply feet by feet by feet.

Ordering the exact volume for a compacted base. Base material shrinks when compacted. Order 10 to 15% more or you will be short by the time the plate compactor finishes.

Using the wrong stone. Pea gravel is comfortable underfoot but rolls and migrates on driveways and slopes. Angular crushed stone locks together; that is what you want under anything with wheels.

Skipping the fabric. Landscape fabric or a woven geotextile under the gravel keeps it from sinking into the soil and cuts down on weeds. On a driveway it can be the difference between a base that lasts and one that ruts in a year.

When to hire a pro

Paths, patio bases, and drainage trenches are straightforward weekend work with a rented plate compactor. A new gravel driveway is a bigger job: it needs grading for drainage, removing topsoil, and building the base in compacted layers. A contractor with a skid steer does in a day what takes a homeowner weeks with a wheelbarrow, and they will know which local stone sizes and base mixes hold up best in your soil.